SKD11, SUS420, SUS440C and the like have conventionally been used as metal injection molding powders for obtaining very hard, highly corrosion-resistant sintered bodies. These steels, in which the hardness is obtained mainly by the use of Cr carbide, exhibit an austenite phase in the sintering temperature range, and have a poor degree of sintering because the speed of elemental movement (diffusion) which promotes sintering is slower than in a ferrite phase. On the other hand, if the temperature is raised to the temperature at which a liquid phase appears in order to promote sintering, a large amount of liquid phase arises at once, carbides are formed as networks at the grain boundaries, and either the strength of the product is seriously diminished or it is deformed to the point that the shape of the product cannot be maintained. To avoid these, it is necessary to proceed with the sintering temperature controlled within an extremely narrow temperature range of ±5° C. or in other words about 10° C. Because of this, it has been necessary to limit the usable region of the sintering furnace, sacrificing productivity.